The present invention relates to wobble detection of optical storage devices, and more particularly, methods and devices for detecting wobbles on an optical disc.
A conventional wobble detection circuit typically comprises a lot of large area components, such as analog automatic gain control (AGC) circuits and analog filters (e.g. an analog low pass filter (LPF) and an analog band pass filter (BPF)). According to the related art, large chip areas are required for implementing the conventional wobble detection circuit since these analog components are operated at a very low frequency. Within some of the analog AGC circuits mentioned before, an envelope detector and an integrator typically occupy a large chip area since the envelope detector and the integrator have to be operated at a very low frequency.
In practice, when implementing respective voltage gain amplifiers (VGAs) in some analog automatic gain control (AGC) circuits, the VGAs should be exactly the same in order to guarantee the quality of the detected wobble signal. As a result, decreasing the size of the VGAs is impractical since it is hard to maintain the balance between the VGAs when the size of the VGAs is small. A novel method for performing wobble detection is therefore required.